Saw this on the YouTubes:
"Hey guys! I've found out how to become Brownie. All you have to do it get to a character select screen and while in the character selection screen press RB, RB, RB, B, B, B, X, then pick any character to become Brownie!
The only requirement is that you need to beat the Salt Factory before you can choose him. It feels like he plays the same as Meat Boy (Like 4-bit, 8-bit, and B&W Meat Boy).
Enjoy!" Another palette swap but cool nonetheless.